Israeli Foreign Minister Tzipi Livni said on Wednesday that giving Iran a seat on the UN Security Council would be "absurd" given the insecurity its policies have caused.
"It is absurd that a state unparalleled in threatening the security of its neighbours and calling for the destruction of another state should be a member of a body whose goal is to further global security," Livni said.
"The significance would be to let a criminal become his own judge," she added.
Her statement came a day after Iranian President Mahmoud Ahmadinejad delivered a new tirade against Israel in a fiery address to the UN General Assembly.
"The Zionist regime is on a definite slope to collapse and there is no way for it to get out of the cesspool created by itself and its supporters," Ahmadinejad said.
Iran has launched a bid for one of the 10 non-permanent member seats on the UN Security Council which becomes vacant in January.
The seat reserved for an Asian nation is currently held by Indonesia. Iran has occupied a Security Council seat only once before, in 1955 and 1956 when it was still ruled by the US-backed Shah.
Israel has never served on the Security Council. It announced in September 2005 that it wished to be a candidate for a seat for the first time but not until 2019.
Israel, the region's sole if undeclared nuclear-armed state, considers Iran its main strategic threat, both because of Tehran's nuclear programme and repeated statements by Ahmadinejad predicting the demise of the Jewish state.
Iran insists its uranium enrichment programme is aimed solely at generating electricity for its growing population and has pushed ahead with it despite three rounds of UN Security Council sanctions.
Livni, who was tasked with forming a government in the wake of Prime Minister Ehud Olmert's resignation earlier this week, is hoping to become Israel's first woman prime minister since Golda Meir.